I have a a salary question related to recruitment agencies?

I went for an interview at a recruitment agency today after seeing an online advertisement for a position that I desperately wanted. The job was advertised at (hypothetically) $85k + super. I was sent to the employer this afternoon for an interview and found that my skill set and experience matched the job and the team was friendly and endearing. They (or the recruitment agency) will be notify the successful applicant within the next 36 hours. I have a sinking feeling that I might have been duped into believing the advertised salary did not include leave loading. This would mean my salary would be $70K which is considerably less than what I bargained for. How would you negotiate your way out of this without upsetting the agency and the potential employer? should I wait till I am offered the position by the agency, get them to confirm the base salary and then tell them that I thought the salary was $85K? and that I would be happy to settle for $80K if they could reduce placement fees?